Conventionally, micro black defects and white defects on a color film (CF) substrate are generally inspected by a total inspection machine, which monitors a defect trend of all kinds of products. The inspection of a black matrix is a first process in color film processes. As illustrated in FIG. 1, main functions of the black matrix lie in:
1. as being a non-transmissible zone of light, distinguishing RGB (red, green, blue) areas; and
2. upon designing a product, it is required to consider affections on chrominance by a size of a width (line width) of a black matrix area, wherein the defects such as overlapping of the RGB areas or light leaking may arise if the line width is small, and the contrast and the chrominance may be caused to be varied if the line width is large.
Thus, during manufacturing of a color film, the inspection of the line width of the black matrix is an important process. Conventionally, the inspection of the line widths of the black matrices by the total inspection machine may be merely implemented by marking lines and then measuring by review lenses. During the measurement, it is required to stop the device which is transmitting color film substrates. Thus, the time duration for measuring is long, and it is difficult to inspect the line width of the black matrix in each color film substrate. Moreover, if the device is stopped for inspecting, a takt time of a product line of the black matrix will be extended, which may affect productivity of the whole color film substrate production line. On the other hand, if the line widths of the black matrices are inspected by total sampling, it will take a long time, and it is difficult to achieve a real-time monitoring, thereby leading to a higher risk of yield loss.